1. Field of the Invention
The present invention relates to a touch sensor that has a display function based on emitted light.
2. Description of the Related Art
A known touch sensor having a display function based on emitted light includes a transparent plate, a decorative layer that represents keys, a substantially transparent touch sensor layer constituting a capacitive touch sensor, and an illumination layer, which functions as an inorganic electro-luminescence (EL) element; these elements are laminated in that order from the front of the touch sensor (see Japanese Unexamined Patent Application Publication No. 2011-150502, for example). In this touch sensor, the decorative layer is illuminated by the illumination layer from the back of the decorative layer so that keys are displayed to the user by transmitted light in the decorative layer. The illumination layer in this touch sensor is comprised of an insulating layer, a transparent electrode layer, a light-emitting body layer, which is an inorganic EL layer, a dielectric layer, a rear electrode layer, and a protecting layer.
An EL element structured so that an organic EL layer is sandwiched between a pair of electrodes is also known (see Japanese Unexamined Patent Application Publication No. 2003-272834, for example). A technology is also known by which this type of organic EL layer is formed by applying a coating made of an organic EL material (see Japanese Unexamined Patent Application Publication No. 2009-26630, for example).